He appealed to the moderate majority to stand up to hardliners hell-bent on leading them over the cliff edge.

Mr Bayliss, assistant general secretary of Britain’s biggest union Unite, insisted there was no mood for strikes among grassroots members. And he cautioned his 1.6million members against repeating the mistakes of the 1980s and being dragged into battles they could not win.

Ex-engineer Mr Bayliss, 57, warned: “Public sector strikes will only deprive the vulnerable of services the Tories want to cut. We’ll be doing the bad guy’s job for him. Strikes will also turn the real victims, our members, into the villains.

“The story will get changed from government savagery to union militancy. The Tories will hit us with even more restrictive laws and working people will look away in disgust.”

Mr Bayliss, who is a candidate in Unite’s leadership election, called for “common sense”.

His remarks will anger hardliners gathering in Manchester today for the TUC conference. But

Mr Bayliss admitted the 12-day strike by BA cabin crew held by Unite over Christmas was a mistake. He said: “They had a good case — but the public and many of our members were so horrified they lost sympathy.

“If I am general secretary of Unite there will NEVER be any strikes called over Christmas.”